Oxidized LDL induced extracellular trap formation in human neutrophils via TLR-PKC-IRAK-MAPK and NADPH-oxidase activation

Awasthi, Deepika; Nagarkoti, Sheela; Kumar, Amit; Dubey, Megha; Singh, Abhishek Kumar; Pathak, Priya; Chandra, Tulika; Barthwal, Manoj Kumar; Dikshit, Madhu

doi:10.1016/j.freeradbiomed.2016.01.004

Cited by 138 publications

(113 citation statements)

References 89 publications

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“…aureus has consistently been described to be a potent inducer of NETosis [12,14,34,40,71,75,104,131–133]. In literature search a variety of other bacteria were reported, that also induced NETosis, although most species are weak NETosis inducers compared to S .…”

Section: Resultsmentioning

confidence: 99%

In vitro induction of NETosis: Comprehensive live imaging comparison and systematic review

et al. 2017

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BackgroundMultiple inducers of in vitro Neutrophil Extracellular Trap (NET) formation (NETosis) have been described. Since there is much variation in study design and results, our aim was to create a systematic review of NETosis inducers and perform a standardized in vitro study of NETosis inducers important in (cardiac) wound healing.MethodsIn vitro NETosis was studied by incubating neutrophils with PMA, living and dead bacteria (S. aureus and E. coli), LPS, (activated) platelets (supernatant), glucose and calcium ionophore Ionomycin using 3-hour periods of time-lapse confocal imaging.ResultsPMA is a consistent and potent inducer of NETosis. Ionomycin also consistently resulted in extrusion of DNA, albeit with a process that differs from the NETosis process induced by PMA. In our standardized experiments, living bacteria were also potent inducers of NETosis, but dead bacteria, LPS, (activated) platelets (supernatant) and glucose did not induce NETosis.ConclusionOur systematic review confirms that there is much variation in study design and results of NETosis induction. Our experimental results confirm that under standardized conditions, PMA, living bacteria and Ionomycin all strongly induce NETosis, but real-time confocal imaging reveal different courses of events.

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Section: Resultsmentioning

confidence: 99%

In vitro induction of NETosis: Comprehensive live imaging comparison and systematic review

et al. 2017

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“…We first tested which stimuli could induce NET in neutrophils in vitro by testing several athero-relevant stimuli (oxLDL and 7-ketocholestero [7KC], the most abundant oxysterol in human oxLDL 25 and atheroma 26 ) and bacterial infection-relevant stimuli (LPS primed with TNF-α) 16, 27 . Neutrophils isolated from peripheral blood of three 58-week-old mice were treated with oxLDL (100μg/ml), 7KC (50μg/ml), or LPS (100ng/ml) with TNF-α priming (10ng/ml pretreatment) for 4 hr.…”

Section: Resultsmentioning

confidence: 99%

Mitochondrial Oxidative Stress Promotes Atherosclerosis and Neutrophil Extracellular Traps in Aged Mice

Wang

et al. 2017

ATVB

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Rationale Mitochondrial oxidative stress (mitoOS) has been shown to be increased in various cell types in human atherosclerosis and with aging. However, the role of cell type-specific mitoOS in atherosclerosis in the setting of advanced age and the molecular mechanisms remain to be determined in vivo. Objective The aim of this study was to examine the role of myeloid-cell mitoOS in atherosclerosis in aged mice. Approach and Results Lethally irradiated Ldl receptor-deficient mice (Ldlr−/−) were reconstituted with bone marrow from either wild type or mitochondrial catalase (mCAT) mice. mCAT transgenic mice contain ectopically expressed human catalase gene in mitochondria, which reduces mitoOS. Starting at the age of 36 weeks, mice were fed the Western-type diet (WD) for 16 weeks. We found that mitoOS in lesional myeloid cells was suppressed in aged mCAT→Ldlr−/− chimeric mice compared to aged controls, and this led to a significant reduction in aortic root atherosclerotic lesion area despite higher plasma cholesterol levels. Neutrophil extracellular traps (NETs), a pro-inflammatory extracellular structure that contributes to atherosclerosis progression, were significantly increased in the lesions of aged mice compared with lesions of younger mice. Aged mCAT→Ldlr−/− mice had less lesional neutrophils and decreased NETs compared with age-matched WT→Ldlr−/− mice, while young mCAT→ and WT→ Ldlr−/− mice had comparable numbers of neutrophils and similar low levels of lesional NETs. Using cultured neutrophils, we showed that suppression of mitoOS reduced 7-ketocholesterol-induced NET release from neutrophils of aged but not younger mice. Conclusions MitoOS in lesional myeloid cells enhanced atherosclerosis development in aged mice, and this enhancement was associated with increased lesional NETs. Thus, mitoOS-induced NET formation is a potentially new therapeutic target to prevent atherosclerosis progression during aging.

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“…OxPAPC was shown to accumulate in atherosclerotic lesions and at other inflamed sites in conditions such as septis and acute lung injury, where it is believed to contribute to disease progression [12]. OxPAPC levels affect a variety of signaling pathways, including kinase pathways involving protein kinase C (PKC), extracellular signal-related kinases 1 and 2 (ERK1/2) or p38 mitogen-activated protein kinase (p38-MAPK) and also increase intracellular calcium levels to promote inflammatory responses [13–15]. Several studies suggest that OxPAPC can also exert anti-inflammatory and protective effect by inhibiting the interaction of LPS with LPS-binding protein and CD14 [16–18].…”

Section: Introductionmentioning

confidence: 99%

Oxidized Phospholipid OxPAPC Activates TRPA1 and Contributes to Chronic Inflammatory Pain in Mice

et al. 2016

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Oxidation products of the naturally occurring phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycerol-3-phosphatidylcholine (PAPC), which are known as OxPAPC, accumulate in atherosclerotic lesions and at other sites of inflammation in conditions such as septic inflammation and acute lung injury to exert pro- or anti-inflammatory effects. It is currently unknown whether OxPAPC also contributes to inflammatory pain and peripheral neuronal excitability in these conditions. Here, we observed that OxPAPC dose-dependently and selectively activated human TRPA1 nociceptive ion channels expressed in HEK293 cells in vitro, without any effect on other TRP channels, including TRPV1, TRPV4 and TRPM8. OxPAPC agonist activity was dependent on essential cysteine and lysine residues within the N-terminus of the TRPA1 channel protein. OxPAPC activated calcium influx into a subset of mouse sensory neurons which were also sensitive to the TRPA1 agonist mustard oil. Neuronal OxPAPC responses were largely abolished in neurons isolated from TRPA1-deficient mice. Intraplantar injection of OxPAPC into the mouse hind paw induced acute pain and persistent mechanical hyperalgesia and this effect was attenuated by the TRPA1 inhibitor, HC-030031. More importantly, we found levels of OxPAPC to be significantly increased in inflamed tissue in a mouse model of chronic inflammatory pain, identified by the binding of an OxPAPC-specific antibody. These findings suggest that TRPA1 is a molecular target for OxPAPC and OxPAPC may contribute to chronic inflammatory pain through TRPA1 activation. Targeting against OxPAPC and TRPA1 signaling pathway may be promising in inflammatory pain treatment.

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Oxidized LDL induced extracellular trap formation in human neutrophils via TLR-PKC-IRAK-MAPK and NADPH-oxidase activation

Cited by 138 publications

References 89 publications

In vitro induction of NETosis: Comprehensive live imaging comparison and systematic review

In vitro induction of NETosis: Comprehensive live imaging comparison and systematic review

Mitochondrial Oxidative Stress Promotes Atherosclerosis and Neutrophil Extracellular Traps in Aged Mice

Oxidized Phospholipid OxPAPC Activates TRPA1 and Contributes to Chronic Inflammatory Pain in Mice

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